Commit 1cec170d authored Aug 26, 2020 by Florian Westphal Committed by David S. Miller Aug 26, 2020

mptcp: free acked data before waiting for more memory



After subflow lock is dropped, more wmem might have been made available.

This fixes a deadlock in mptcp_connect.sh 'mmap' mode: wmem is exhausted.
But as the mptcp socket holds on to already-acked data (for retransmit)
no wakeup will occur.

Using 'goto restart' calls mptcp_clean_una(sk) which will free pages
that have been acked completely in the mean time.

Fixes: fb529e62 ("mptcp: break and restart in case mptcp sndbuf is full")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 09e31cf0

net/mptcp/protocol.c

+1 −2

Original line number	Diff line number	Diff line
		@@ -892,7 +892,6 @@ restart:
		goto out;
		}

		wait_for_sndbuf:
		__mptcp_flush_join_list(msk);
		ssk = mptcp_subflow_get_send(msk);
		while (!sk_stream_memory_free(sk) \|\|
		@@ -982,7 +981,7 @@ wait_for_sndbuf:
		*/
		mptcp_set_timeout(sk, ssk);
		release_sock(ssk);
		goto wait_for_sndbuf;
		goto restart;
		}
		}
		}

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